The research is designed to elucidate the manner in which the decision to move the eyes is translated into the pattern of excitatory and inhibitory neural impulses channeled to the muscle fibers of the twelve extraocular muscles in the primate. Experiments are to be carried out on monkeys. Visual and vestibular stimulation is given to an alert monkey in whom electrodes have been implanted and the eye movement responses are correlated to unit firing. Such experiments, and the knowledge obtained from post-mortem histology, will enable the tracing of the supranuclear pathways which are utilized by the saccadic, pursuit, vergence and vestibular eye movement systems. Specific ablations in these pathways permit identification of the role of certain structures (e.g., flocculus and other parts of cerebellum) in eye movement control. By electrical stimulation or focused lesions, known clinical neuro-ophthalmological syndromes can be stimulated and their origin and possible modes of alleviation studied.